JP6959306B2 - Optical system and surgical instruments having the optical system - Google Patents

Description

Detailed description of the invention

The present invention is an optical system comprising a distal optical assembly, a proximal optical assembly, and an image sensor, wherein the distal and proximal optical assemblies define the optical path and the distal optical assembly. With respect to the optical system, incident light beams from a field of view located in the space of the object are connected into the proximal optical assembly, which directs these optical beams onto the photosensitive surface of the image sensor. .. The present invention also relates to surgical instruments having such an optical system.

The optical elements of the optical system, typically one or more lenses, map an incident light beam from the field of view onto the photosensitive surface of the image sensor. These light beams are generated in the optical path defined by the optical assembly of the optical system, or more precisely by its optical elements.

The field of view of an optical system refers to a region or spacing of viewing angles that allows the optical system to sense events or changes in the space of an object. The incident light beam from the field of view is mapped onto the photosensitive surface of the image sensor. When using a rectangular image sensor, the field of view is defined by a horizontal viewing angle and a vertical viewing angle. The horizontal and vertical viewing angles are limited by the boundaries of the imaging format, but the boundaries of the imaging format depend on the dimensions and shape of the image sensor. With a rectangular image sensor, the vertical viewing angle is usually smaller than the horizontal viewing angle (horizontal format). Therefore, the horizontal viewing angle and the vertical viewing angle are the maximum incident angles at which the light beam can be incident on the optical system and can be imaged on the photosensitive surface of the image sensor.

When the angle at which the light beam is incident on the optical system is large, reflection occurs in the optical element. These light beams also cause diffuse scattering or reflection on the tube or lens barrel in which the optics of the optical system are housed. These reflections, often referred to as "flares" or "lens flares," adversely affect the image quality of the optical system.

Conventionally, the incidence of such a light beam is reduced by a mechanical shield or aperture of the optical system. However, obstructions and openings often result in intense vignetting, i.e., darkening the edges of the image. Also, such shields require very tight manufacturing tolerances for the optics.

An object of the present invention is to provide an improved optical system and an improved surgical instrument having such an optical system, the optical system for an incident light beam from outside the field of view. The sensitivity is particularly low.

An object of the present invention is realized by an optical system including a distal optical assembly, a proximal optical assembly, and an image sensor, in which the distal and proximal optical assemblies define an optical path. The distal optical assembly connects the incident light beams from the field of view located in the space of the object into the proximal optical assembly, and the proximal optical assembly connects these light beams to the image sensor. This optical system is developed by a group of prisms having at least one prism arranged in the optical path, and the group of prisms limits the field of view of the optical system on at least one side. ing.

Advantageously, the prism group provides an angle-dependent optical filter that reflects an incident light beam incident on the optical system from outside the field of view to the outside of the optical path. Vignetting does not occur and no particularly strict requirements are imposed on the alignment and adjustment of the prisms of the optical system. In addition, the prism group is less expensive to manufacture and can be incorporated into the optical system without much design effort.

In particular, the prism group is rotatably incorporated into the optical system. For example, the prisms of an optical system can rotate about an optical axis of the optical system, in particular an axis that at least substantially corresponds to the optical axis of the distal optical assembly of the optical system. Advantageously, the rotation of the prism group allows the field of view to be variably limited on various sides by utilizing the prism group.

According to another effective embodiment, at least one prism has a interface that totally reflects the incident light beam from outside the field of view out of the optical path. This interface is the interface between a medium with a higher optical density and a medium with a lower optical density, such as a glass / air interface.

Here, in particular, the outwardly reflected light beam is incident on the distal optical assembly on the side of the field of view where the prisms limit the field of view.
A particularly effective embodiment of a group of prisms utilizing total internal reflection at one interface is that the prism group comprises at least first and second prisms, the first prism has a boundary surface where total internal reflection occurs, and the second prism. Is arranged adjacent to this interface and is obtained according to a further exemplary embodiment in which a first void is present between the first and second prisms.

Therefore, in other words, the first prism and the second prism are arranged directly adjacent to each other. Instead of providing a gap between the first prism and the second prism, a connecting portion of the two prisms is provided on the boundary surface where total reflection occurs, and in order to connect the two prisms, the material of the first prism is used. Also, materials with low optical density are used.

Total internal reflection occurs when light hits the interface between a medium with a higher optical density and a medium with a lower optical density. In this process, the totally reflected light hits the interface at an angle greater than the critical angle for the two given materials. This angle is measured relative to a perpendicular line perpendicular to the interface. The totally reflected beam always spreads in a medium with higher optical density. The glass / air interface is a typical example of how easy it is to obtain this situation where the light beam is totally reflected.

According to another embodiment, the optical system is developed by a group of prisms that also has a third prism, and the first to third prisms are mirror-symmetric with respect to a vertical plane perpendicular to the optical axis of the prism group. It is designed to be.

An effective mirror plane symmetric system consists of a first right-angled prism as a first prism, an isosceles triangular prism as a second prism, and a second right-angled prism as a third prism in order in the direction in which light is incident. It has a group of prisms. The second prism includes a second interface where total reflection occurs. The third prism is arranged adjacent to the second boundary surface, and a second gap exists between the second prism and the third prism.

Further, instead of the second void, a material having an optical density lower than that of the material of the second prism can be provided.
The field of view is preferably limited on two sides by reflections on the first and second interface. According to a further exemplary embodiment, the field of view can be similarly restricted on yet another side by adding another prism.

Specifically, the first and second interface planes are inclined in different directions so that the light beam reflected out of the optical path exits the optical path in different directions.
Here, the first and second boundary surfaces are particularly inclined with respect to the first axis and the second axis. The first and second axes are at least substantially parallel to each other or oriented perpendicular to each other. The boundary surface where total reflection occurs is oriented parallel to the side of the isosceles triangle prism that functions as the second prism, for example. Here, the first interface is provided by the surface of the first prism, while the second interface is provided by the surface of the second prism.

According to another embodiment, the optics are developed by at least one prism of the prism group, which is a right-angled columnar prism. At least one prism includes two optically effective prism surfaces forming an acute angle and an optically ineffective surface on opposite sides of the acute angle. The first plane having the first optically effective prism surface, the second plane having the second optically effective prism surface, and the third plane having the surface form a triangle which is the bottom surface of the prism in at least one region.

Therefore, in other words, the first to third planes form a triangle. An optically effective interface is understood to be an interface in the optical path. The bottom region of the prism does not necessarily have to be triangular. For example, it may be wedge-shaped or truncated triangle.

According to a more effective embodiment, the prism group includes at least a first prism and a second prism, and the first and second prisms have a first acute angle of the first prism and a second acute angle of the second prism. Are arranged so that they are on both sides of each other.

In other words, the first acute angle and the second acute angle do not extend in opposite directions.
Here, the first and second prisms are arranged in order in the direction in which light is incident, and the first prism is a right-angle prism. This prism group embodiment is particularly simple to implement and at the same time very optically effective.

In another effective embodiment, in the optics, the prism group is part of the distal optical assembly, the distal optical assembly specifically comprises an incident lens, and the prism group is an incident lens in the direction in which the light is incident. It is developed by being placed immediately after.

This configuration of the prism group is particularly effective because the incident light beam from outside the field of view, which causes a light scattering phenomenon in the optical system, has already been removed from the optical path at the beginning of the optical system. This is very helpful in improving the image quality of the optical system.

Moreover, such a configuration is advantageous because the proximal optical assembly is completely unaffected by the means taken to improve image quality. Therefore, the optics are very adaptable to the design of the proximal optical assembly.

The optical system particularly comprises at least one image sensor. Further, this optical system is particularly an optical system for recording stereoscopic image data.
Thus, according to another exemplary embodiment, the proximal optical assembly comprises a left lens system channel with a left optical axis and a right lens system channel with a right optical axis. The left and right lens system channels are designed in the same way, and the left and right optical axes extend parallel to each other. The distal optical assembly is configured such that incident light from the space of the object is directed to both the left and right lens channels of the proximal optical assembly.

Such optics are particularly suitable for use within stereoscopic video endoscopes.
An object of the present invention is further realized by a surgical instrument having an optical system according to one or more of the above-described embodiments, particularly an endoscope, more specifically a stereoscopic video endoscope.

This optical system is particularly an optical system for surgical instruments, and more specifically, an optical system for a stereoscopic video endoscope.
Similar or similar effects as those already mentioned for the optics themselves apply to surgical instruments, especially endoscopes. It is possible to identify particularly suitable optics that are very insensitive to light scattering, which is also easy and efficient to manufacture.

Further features of the present invention will become apparent from the description of each embodiment of the present invention, along with the claims and drawings included in the present application. The embodiments according to the present invention can satisfy individual features or combinations of some features.

The present invention will be described below with reference to the respective drawings, using exemplary embodiments, without limiting the concept of the invention. Disclosure of all details relating to the present invention, which is not described in detail in the text, is also clearly shown in each drawing.

The optical system according to the prior art is shown in a schematicly simplified vertical cross-sectional view. An optical system according to an exemplary embodiment is shown in a schematicly simplified vertical sectional view. The prism group of the optical system of FIG. 2 is shown in a schematicly simplified vertical cross-sectional view. Another depiction of the prism group of FIG. 3 is shown in a schematicly simplified vertical cross-sectional view. It is a schematic simplification of another optical system according to the prior art, showing only the lens system channel on the left side of the proximal optical assembly. It shows the optical system of a stereoscopic video endoscope according to an exemplary embodiment with prisms, and only the lens system channel on the left side of the proximal optical assembly is shown.

In each drawing, the same or similar types of elements or parts are designated by the same reference numerals to eliminate the need for redundant explanations in each case.
FIG. 1 shows a schematicly simplified vertical cross-sectional view of the optical system 2 according to the prior art. The incident light beam 6 from the space 4 of the object (only one of which has a reference code for clarity) first hits the incident window 8. The optical system 2 is, for example, a component of a surgical instrument, and further, for example, an optical system 2 of an endoscope. Inside the endoscope, the incident window 8 airtightly seals the internal space of the endoscope shaft with respect to the external space, that is, the space 4 of the object, at the distal end of the shaft. As the light beam 6 passes through the incident window 8, the light beam 6 enters the distal optical assembly 10 and then reaches the proximal optical assembly 12. The distal optical assembly 10 and the proximal optical assembly 12 define the optical path 14 in the optical system 2.

The field of view 20 is located in the space 4 of the object and is defined by a horizontal viewing angle and a vertical viewing angle. The vertical cross-sectional view shown in FIG. 1 shows, for example, a cross section along a vertical plane. Therefore, the vertical viewing angle is shown, which is the angle between the optical axis 16 of the optical system 2 and the light beam 6 that just hits the photosensitive surface 19 of the image sensor 18. The field of view 20 is schematically shown by an arrow in FIG. The distal optical assembly 10 and the proximal optical assembly 12 image the incident light beams 6, 6'from the field of view 20 on the photosensitive surface 19 of the image sensor 18.

However, when the light beam 6 ″ from outside the range of the field of view 20 is incident on the optical system 2, diffuse scattering or reflection occurs in the optical system 2 due to the light beam 6 ″. For example, diffuse scattering occurs on the inner wall of the cylinder of the optical system 2 or the lens barrel. This is shown by a star in FIG. 1, which attempts to represent the scattering center 22. This reflection or scattering causes "flare" or "lens flare", which is a phenomenon that adversely affects the image quality of the optical system 2.

FIG. 2 shows the optical system 2 according to an exemplary embodiment in a longitudinal sectional view that is also schematically simplified along a vertical sectional view. The optical system 2 includes a distal optical assembly 10 and a proximal optical assembly 12. The distal optical assembly 10 and the proximal optical assembly 12 define an optical path 14 in the optical system 2. The light beam 6 in the field of view 20 (only one of them is shown as an example) incident on the optical system 2 from the space 4 of the object is imaged on the photosensitive surface 19 of the image sensor 18.

The optical system 2 according to the illustrated embodiment includes a prism group 24 arranged in an optical path 14. The prism group 24 includes at least one prism 30, 32, 34, and limits the field of view 20 of the optical system 2 on at least one side. In addition to the prism group 24, the distal optical assembly 10 also has an incident lens 26 and an exit lens 28. At least one prism 30, 32, 34 of the prism group 24 has boundary surfaces 36, 38 that totally reflect the incident light beam 6'' incident on the optical system 2 from outside the range of the field of view 20 to the outside of the optical path 14. Be prepared.

The prism group 24 shown in FIG. 2 includes, for example, a first prism 30, a second prism 32, and a third prism 34. The first prism 30 provides a first interface 36 that reflects the first light beam 40 (indicated by an arrow) out of the optical path 14. The second prism 32 provides a second interface 38 that reflects the second light beam 42 (indicated by an arrow) out of the optical path 14 in another direction.

The light beam reflected outside the optical path 14 is incident on the optical system 2 as a light beam 6 ″ and a light beam 6 ″ from outside the range of the field of view 20. In FIG. 2, the incident light beam 6'''from outside the range of the field of view 20 under the optical system 2 is totally reflected as the first light beam 40 on the first boundary surface 36 and excluded from the optical path 14. There is. The incident light beam 6 ″ from outside the range of the field of view 20 on the upper side of the optical system 2 is totally reflected as the second light beam 42 on the second boundary surface 38, and is thus reflected so as to deviate from the optical path 14. NS.

The prism group 24 limits the field of view 20 on two opposite sides, for example, the upper and lower horizontal boundaries of the field of view 20. The incident light beams 6 ″ and 6 ″ in the optical system 2 incident from outside the range of the field of view 20 are reflected outside the optical path 14 on the upper side and the lower side of the field of view 20. Similarly, rotating the prism group 24 around the optical axis 16 also brings restrictions to the left or right side of the field of view 20, for example, at the vertical boundary of the field of view 20. To do this, the prism group 24 must be rotated 90 ° about the optical axis 16 and further adapted to the required horizontal viewing angle (probably greater than the vertical viewing angle). In order to make such a fit, for example, the inclinations of the boundary surfaces 36 and 38 with respect to the optical axis 16 are appropriately selected.

It is also possible to add another prism group 24 (not shown) in FIG. Using such an exemplary embodiment, the first prism group 24 is configured as the prism group 24 shown in FIG. 2, and the second prism group follows in the direction in which the light is incident. It is considered that the light axis 16 is rotated by 90 ° around the center of the optical axis 16 and arranged. Therefore, the limitation of the field of view 20 could be realized at both the horizontal and vertical boundaries of the field of view 20.

FIG. 3 shows the prism group 24 known by FIG. 2 in a longitudinal sectional view also schematically simplified. The prism group 24 is embodied mirror-symmetrically with respect to the partially shown vertical plane 52. The vertical surface 52 is perpendicular to the optical axis 16. The prisms 30, 32, and 34 of the prism group 24 are preferably prisms having a right-angled column shape.

The first prism 30 and the third prism 34 of the prism group 24 are also right-angle prisms. The second prism 32 is an isosceles triangle prism. The first prism 30 has a first interface 36 where total reflection occurs. A first gap 46 exists between the first boundary surface 36 and the incident surface 44 of the second prism 32. A second gap 50 exists between the second boundary surface 38, which is the emission region of the second prism 32, and the incident surface 48 of the third prism 34. In each case, on both the first interface 36 and the second interface 38, the transition is from a medium with a higher optical density, eg, the material of the first prism 30 or the material of the second prism 32, which is glass. It occurs everywhere in the medium with lower optical density, that is, the air in the respective voids 46, 50. The light beams 40 and 42 (see FIG. 2) are totally reflected by the first boundary surface 36 and the second boundary surface 38.

The prisms 30, 32, and 34 are arranged adjacent to each other. For this reason, there are no additional optics between the prisms 30, 32, 34, and therefore the prism group 24 does not have additional optics. In particular, the incident surface 44 of the second prism 32 is arranged adjacent to the first boundary surface 36 of the first prism 30. Only the first void 46 is between these two boundary surfaces 36 and 44. The same applies to the arrangement of the second prism 32 and the third prism 34. Again, another incident surface 48 of the third prism 34 is located adjacent to the second interface 38. Only the second void 50 is between these two boundary surfaces 38 and 48. According to another exemplary embodiment, instead of the voids 46,50, the gaps are filled with a medium with a lower optical density. Importantly, the optical density of this medium is lower than the optical density of the material of the first prism 30 in the case of the first void 46, and lower than the optical density of the material of the second prism 32 in the case of the second void 50. It is low. The prisms 30, 32, and 34 can be joined to each other, for example.

The first boundary surface 36 and the second boundary surface 38 are inclined in different directions. As a result, the light beams 40 and 42 reflected out of the optical path 14 are reflected from the light beams 40 and 42 in different directions. Since the prism group 24 is designed symmetrically, the angles at which the boundary surfaces 36 and 38 are inclined are the same. Moreover, these ramps are on axes parallel to each other.

FIG. 4 shows another schematic view of the prism group 24. The first prism 30 includes two optically effective prism surfaces 54, 54'forming an acute angle α. Further, the first prism 30 includes an optical non-effective surface 56 on the opposite side of the acute angle α. The first optically effective prism surface 54 is on the first plane E1 (indicated by the chain line). The second optically effective prism surface 54'is on the second plane E2. The surface 56 is on the third plane E3. The first to third planes E1, E2, and E3 form a triangular side, which is at least a part of the bottom surface region of the first prism 30 having a right-angled pillar shape. The actual bottom area of the prism 32 is a triangle with a truncated top. Corresponding designs can also be found in the second prism 32 and the third prism 34. Each of the two optically effective prism planes has an acute angle as well, but this acute angle is on the opposite side of the other plane of the optically ineffective prisms 32, 34. These surfaces are on a plane that forms a triangle, part of which forms the bottom region of the prism. For example, in addition to the first prism 30, the prism group 24 has a second prism 32 designed like the first prism 30 in this sense. The second prism 32 also has optically effective prism surfaces 54 ″, 54 ′ ″, and these surfaces face the surface 56 ′ and form an acute angle β.

The first prism 30 and the second prism 32 are arranged so that the first acute angle α of the first prism 30 and the second acute angle β of the second prism 32 are on both sides of the prism group 24 facing each other. Therefore, the acute angles α and β are on opposite sides of each other.

The above-mentioned design policy is also applied to the prism group 24 of the exemplary embodiment of FIG. 6, but the details of the exemplary embodiment of FIG. 6 will be described below.
First, FIG. 5 shows another optical system 2 according to the prior art. The optical system 2 is used, for example, in a stereoscopic video endoscope having a horizontal line of sight. The optical system 2 is located behind the incident window 8 in the endoscope shaft, and the light beam 6 is incident into the optical system 2 from the field of view 20 through the incident window 8. The light beam 6 first incidents on the distal optical assembly 10 having the incident lens 26, the deflecting prism group 58, and the exit lens 28. The proximal optical assembly 12 of the optical system 2 shown here has left and right lens system channels. In FIG. 5, only the left lens system channel 60 is shown as an example. The left image sensor 18L is located in the left lens system channel 60. The incident light beam 6 incident on the optical system 2 from the field of view 20 is located on the left image sensor 18L and on the right image sensor (not shown) in the optical path 14, the distal optical assembly 10 and the proximal optical assembly 12. Is imaged by. The incident light beam 6 ″ from outside the field of view 20 generates a ghost image in the optical system 2 due to multiple reflections. This light beam is reflected twice at the rear side 57 of the second deflection prism 61 of the deflection prism group 58 and twice at the front side 59.

FIG. 6 shows another optical system 2 according to an exemplary embodiment. The optical system 2 is, for example, the optical system 2 of a stereoscopic video endoscope. The optical system 2 has a prism group 24 as a part of the deflection prism group 58, and the prism group 24 uses an incident light beam 6 ″ from outside the range of the field of view 20 as a first light beam 40 and an optical path 14 It has a boundary surface 36 that reflects off the surface of the light. For this purpose, the prism group 24 has a first prism 30 and a second prism 32. Again, it is preferable that a first void is provided between the first boundary surfaces 36 of the first prism 30 so that total reflection occurs at the boundary surface 36. The first prism 30 and the second prism 32 particularly replace the first deflection prism 62 of the deflection prism group 58, that is, (in addition to the total internal reflection of the light beam 6'' not incident from the field of view 20). It is designed to provide the same optical effect.

It is particularly effective that the prism group 24 is arranged directly adjacent to the incident lens 26. This also applies to the exemplary embodiments of FIGS. 2 and 6. The prism group 24 is in each case a part of the distal optical assembly 10 and directly removes unwanted scattered light at the leading portion of the optical system 2. As a result, the imaging quality of the optical system 2 is improved.

All the features mentioned, including those shown only in the drawings, and the individual features disclosed in combination with other features are also important in the present invention, alone and in combination. It is considered to be. Individual features, or combinations of several features, can be realized by each embodiment of the present invention. Within the scope of the present invention, features expressed using terms such as "particularly" or "preferably" are understood as features that are optionally used.

2 ... Optical system, 4 ... Space of object, 6,6', 6'', 6'''... Light beam, 8 ... Incident window, 10 ... Distal optical assembly, 12 ... Proximal optical assembly, 14 ... optical path, 16 ... optical axis, 18 ... image sensor, 19 ... photosensitive surface, 20 ... field of view, 22 ... scattering center, 24 ... prism group, 26 ... incident lens, 28 ... exit lens, 30 ... first prism, 32 ... 2nd prism, 34 ... 3rd prism, 36 ... 1st interface, 38 ... 2nd interface, 40 ... 1st light beam, 42 ... 2nd light beam, 44 ... Incident region, 46 ... 1st void, 48 ... another incident region, 50 ... second void, 52 ... vertical plane, 54, 54'... optically effective prism plane, 56 ... plane, 57 ... rear side, 58 ... deflection prism group, 59 ... front side, 60 ... left side Lens system channel, 61 ... second deflection prism, 62 ... first deflection prism, E1, E2, E3 ... plane.

Claims (7)

An optical system (2) comprising a distal optical assembly (10), a proximal optical assembly (12), and an image sensor (18), the distal and proximal optical assemblies (10, 12) defines the optical path (14), and the distal optical assembly (10) is an incident light beam (6,6') from a field of view (20) located within the space (4) of the object. Into the proximal optical assembly (12), the proximal optical assembly (12) directs the light beam (6,6') onto the photosensitive surface (19) of the image sensor (18). In the optical system (2) leading to, the prism group (24) having at least one prism (30, 32, 34) arranged in the optical path (14) is characterized by the prism group (24). Limits the field of view (20) of the optical system (2) on at least one side, and the at least one prism (30, 32, 34) is incident from outside the range of the field of view (20). It has a boundary surface (36, 38) that reflects an optical beam (6 ″, 6 ′ ″) out of the optical path (14) by total reflection, and at least one of the prism groups (24). The prisms (30, 32, 34) have a right-angled column shape having two optically effective prism surfaces (54, 54') forming a sharp angle α and an optically non-effective surface (56) on opposite sides of the sharp angle α. A first plane (E1) having a first optically effective prism surface (54) and a second plane (E2) having a second optically effective prism surface (54'), which are prisms (30, 32, 34). said face third plane in which the (56) (E3) are both, to forming a triangle is a bottom surface of the prism in at least one region, the at least one prism (30, 32, 34) has, in order from the incident side The incident light beam (6, 6') having the first prism (30) and the second prism (32) and within the visual field (20) range is any of the first and second prisms (30, 32). The optical system (2), characterized in that it passes through the first and second prisms (30, 32) without being totally reflected on the surface. The outwardly reflected light beams (40, 42) are on the side of the field of view (20) where the prisms (24) limit the field of view (20), the distal optical assembly (10). The optical system (2) according to claim 1, wherein the optical system is incident on. The prism group (24) includes at least the first and second prisms (30, 32), the first prism (30) includes the boundary surface (36) where total reflection occurs, and the second prism (32). Is arranged adjacent to the boundary surface (36), and is characterized in that a first void (46) exists between the first prism (30) and the second prism (32). The optical system (2) according to claim 1 or 2. The prism group (24) includes at least a first prism (30) and a second prism (32), and the first and second prisms (30, 32) have a first acute angle α of the first prism (30). The optical system (2) according to claim 1, wherein the second acute-angled β of the second prism (32) is arranged on both sides of the prism group (24) facing each other. .. The fourth aspect of the present invention, wherein the first and second prisms (30, 32) are arranged in order in the direction in which light is incident, and the first prism (30) is a right-angled prism. Optical system (2). The prism group (24) is a part of the distal optical assembly (10), the distal optical assembly (10) particularly includes an incident lens (26), and the prism group (24) is illuminated by light. The optical system (2) according to any one of claims 1 to 5, wherein the optical system (2) is arranged immediately after the incident lens (26) in the incident direction. A surgical instrument having the optical system (2) according to any one of claims 1 to 6, particularly an endoscope.

Images